MyBatis解决BLOB中文乱码问题

Blob在java中是java.sql.Blob，这个对象不能用来做Java实体变量，而应该使用byte[]。对于bolb，一般用于对图片的数据库存储，原理是把图片流存为二进制字节码，然后进行的一种存储方式，在java中对应byte［］数组。

java 与mysql 数据类型对照

类型名称	显示长度	数据库类型	JAVA类型	JDBC类型索引(int)	描述
VARCHAR	L+N	VARCHAR	java.lang.String	12
CHAR	N	CHAR	java.lang.String	1
BLOB	L+N	BLOB	java.lang.byte[]	-4
TEXT	65535	VARCHAR	java.lang.String	-1
INTEGER	4	INTEGER UNSIGNED	java.lang.Long	4
TINYINT	3	TINYINT UNSIGNED	java.lang.Integer	-6
SMALLINT	5	SMALLINT UNSIGNED	java.lang.Integer	5
MEDIUMINT	8	MEDIUMINT UNSIGNED	java.lang.Integer	4
BIT	1	BIT	java.lang.Boolean	-7
BIGINT	20	BIGINT UNSIGNED	java.math.BigInteger	-5
FLOAT	4+8	FLOAT	java.lang.Float	7
DOUBLE	22	DOUBLE	java.lang.Double	8
DECIMAL	11	DECIMAL	java.math.BigDecimal	3
BOOLEAN	1	同TINYINT
ID	11	PK (INTEGER UNSIGNED)	java.lang.Long	4
DATE	10	DATE	java.sql.Date	91
TIME	8	TIME	java.sql.Time	92
DATETIME	19	DATETIME	java.sql.Timestamp	93
TIMESTAMP	19	TIMESTAMP	java.sql.Timestamp	93
YEAR	4	YEAR	java.sql.Date	91

下面用示例来讲解如何处理数据库字段BLOB类型。

BLOB示例讲解

SQL：构建一张数据表

/*
Navicat MySQL Data Transfer

Source Server         : 10.10.10.117-8066-test
Source Server Version : 50629
Source Host           : 10.10.10.117:8066
Source Database       : cvnavidb

Target Server Type    : MYSQL
Target Server Version : 50629
File Encoding         : 65001

Date: 2017-11-23 13:40:53
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `t_transparent_info_send_log`
-- ----------------------------
DROP TABLE IF EXISTS `t_transparent_info_send_log`;
CREATE TABLE `t_transparent_info_send_log` (
  `F_ID` bigint(20) NOT NULL COMMENT '数据ID',
  `F_TYPE` smallint(6) NOT NULL COMMENT '类型',
  `F_ORDER_ID` bigint(20) NOT NULL COMMENT '命令编号',
  `F_DATA` blob,
  `F_ENTERPRISE_ID` bigint(20) DEFAULT NULL COMMENT '运维用户该值为 00000000',
  PRIMARY KEY (`F_ID`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='数据发送记录';

Entity：F_DATA字段是BLOB类型的

@TableName("t_transparent_info_send_log")
public class TransparentinfoSendlog implements Serializable{

    private static final long serialVersionUID = 1L;

    @TableField("F_ID")
    private Long id;

    @TableField("F_TYPE")
    private Integer type;

    @TableField("F_ORDER_ID")
    private Long orderId;

    @TableField("F_ENTERPRISE_ID")
    private Long enterpriseId;

    @TableField("F_DATA")
    private byte[] data;
    private String dataStr;

    private Long vehicleId;
    private String plateCode;
    private String plateColor;
    private Date sendTime;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Integer getType() {
        return type;
    }

    public void setType(Integer type) {
        this.type = type;
    }

    public Long getOrderId() {
        return orderId;
    }

    public void setOrderId(Long orderId) {
        this.orderId = orderId;
    }

    public Long getEnterpriseId() {
        return enterpriseId;
    }

    public void setEnterpriseId(Long enterpriseId) {
        this.enterpriseId = enterpriseId;
    }

    public byte[] getData() {
        return data;
    }

    public void setData(byte[] data) {
        this.data = data;
    }

    public Long getVehicleId() {
        return vehicleId;
    }

    public void setVehicleId(Long vehicleId) {
        this.vehicleId = vehicleId;
    }

    public String getPlateCode() {
        return plateCode;
    }

    public void setPlateCode(String plateCode) {
        this.plateCode = plateCode;
    }

    public String getPlateColor() {
        return plateColor;
    }

    public void setPlateColor(String plateColor) {
        this.plateColor = plateColor;
    }

    public Date getSendTime() {
        return sendTime;
    }

    public void setSendTime(Date sendTime) {
        this.sendTime = sendTime;
    }

    public String getDataStr() {
        if(null!=data){
            dataStr=new String(data);
        }
        return dataStr;
    }
}

Mapper接口：定义SQL接口访问方法

package com.cvnavi.service.transparentinfo.mapper;

import com.baomidou.mybatisplus.plugins.pagination.Pagination;
import com.cvnavi.bean.sys.user.User;
import com.cvnavi.bean.transparentinfo.TransparentinfoSendlog;
import com.cvnavi.core.base.BaseMapper;
import org.apache.ibatis.annotations.Param;
import java.util.List;

public interface TransparentinfoSendlogMapper extends BaseMapper {

    /**查询数据下发列表*/
    public List getTransparentinfoSendlogList(@Param("transparentinfoSendlog") TransparentinfoSendlog transparentinfoSendlog, @Param("usr") User user, Pagination pagination);

    /**新增数据下发操作*/
    public int insertTransparentinfoSendlog(@Param("transparentinfoSendlog") TransparentinfoSendlog transparentinfoSendlog);

}

Mapper XML配置:主要看插入和查询方法

  
    
    
    
    
    

    
    
    
    
  

  
    F_ID, F_TYPE, F_ORDER_ID, F_ENTERPRISE_ID,F_DATA
  

  
    select
    s.F_ID,
    s.F_TYPE,
    s.F_ORDER_ID,
    s.F_ENTERPRISE_ID,
    s.F_DATA,
    v.F_PLATE_CODE plateCode,
    v.F_PLATE_COLOR plateColor,
    o.F_SEND_TIME sendTime
    from t_transparent_info_send_log s
    left join t_orderinfo o on o.F_ID=s.F_ORDER_ID
    left join t_vehicle v on v.F_ID=o.F_VEHICLE_ID
    LEFT JOIN T_VEHICLE_FLEET TF on TF.F_VEHICLE_ID = v.F_ID and TF.F_TYPE = 1
    where 1=1
    
      AND s.F_ID = #{transparentinfoSendlog.id}
    
    
      AND s.F_TYPE = #{transparentinfoSendlog.type}
    
    
      AND o.F_VEHICLE_ID = #{transparentinfoSendlog.vehicleId}
    
    
    
      AND v.F_ENTERPRISE_ID IN (${usr.enterpriseIds})
      
        
          
            AND TF.F_FLEET_ID IN (${usr.fleetIds})
          
          
            AND 1 = 2
          
        
      
    
    order by o.F_ID desc
  

  
    insert into t_transparent_info_send_log
    
      
        F_ID,
      
      
        F_TYPE,
      
      
        F_ORDER_ID,
      
      
        F_ENTERPRISE_ID,
      
      
        F_DATA,
      
    
    
      
        #{transparentinfoSendlog.id,jdbcType=BIGINT},
      
      
        #{transparentinfoSendlog.type,jdbcType=SMALLINT},
      
      
        #{transparentinfoSendlog.orderId,jdbcType=BIGINT},
      
      
        #{transparentinfoSendlog.enterpriseId,jdbcType=BIGINT},
      
      
        #{transparentinfoSendlog.data},
      
    
  

处理Blob后前端只需要使用dataStr字段就可以看到效果了。